Performance analysis and modernization of a deflection system based on the downhole hammer

Introduction. The method of rotary-percussion drilling with downhole hammers is widely used in mining and geological exploration and is also one of the most promising due to the high well flow rates combined with the durability and reliability of designs used in method implementation. One of the main constraints for field use is the lack of a commercially available deflection system capable of adjusting the direction of the wells with high mechanical speed without reducing the technological parameters of drilling. Research aim is to analyze the performance and modernize the designs of the deflection system based on the downhole machine from the point of view of increasing the accuracy of hole deviation change, as well as to make a dependence synthesis to determine the intensity of the hole deviation change when implementing the mechanism of rock destruction by eccentric impact pulses. Research methodology. The study is based on a set of methods of basic scientific research, in particular analysis, synthesis, formalization, abstraction. Conclusions. Dependence is given for determining the intensity of the hole deviation change depending on the impact system parameters. The working conditions of the hammer with a displaced center of gravity in the design of the deflection system are investigated, an empirical dependence is given for determining the magnitude of the orientation error, and recommendations are given for its reduction. The area of possible application of the presented technical solution is analyzed.

Modernization of rock-cutting tool for rotary-percussion drilling that implements eccentric application of impact pulses

Rotary percussion drilling with pneumatic hammers is a promising, high-performance method widely used in the practice of geological exploration, the performance of which is determined mainly by pressure and the amount of cleaning agent supplied by the compressor. The parameters of commercially available high-pressure compressors do not allow drilling at a depth of more than 300 meters, which is one of the main limiting factors of its practical application in production conditions. One of the ways to improve the performance of the rotary-percussion drilling of wells, and at the same time the maximum depth of drilled wells is to improve the mechanism of rock destruction by applying eccentric impact pulses to the drilling tool, which will make it possible to implement more actively the tangential component of the impact pulse that affects the shape and the volumes of the fracture holes being formed, providing additional splitting of the rock in the direction of the rock face. The paper discusses the ways to perfect the known designs of bits for rotary-percussion drilling of wells implementing eccentric application of impact impulses, issues of geometric substantiation of the shape of an eccentric protrusion on a drill bit torus shim for rotary-percussion drilling and oscillations of torus shim when transmitting eccentric impact pulses from the point of view of enhancement durability of a construction and accuracy of transfer of eccentric impact pulses.

Numerical Simulation of Pipeline Deformation Caused by Rockfall Impact

Rockfall impact is one of the fatal hazards in pipeline transportation of oil and gas. The deformation of oil and gas pipeline caused by rockfall impact was investigated using the finite element method in this paper. Pipeline deformations under radial impact, longitudinal inclined impact, transverse inclined impact, and lateral eccentric impact of spherical and cube rockfalls were discussed, respectively. The effects of impact angle and eccentricity on the plastic strain of pipeline were analyzed. The results show that the crater depth on pipeline caused by spherical rockfall impact is deeper than by cube rockfall impact with the same volume. In the inclined impact condition, the maximum plastic strain of crater caused by spherical rockfall impact appears when incidence angleαis45°. The pipeline is prone to rupture under the cube rockfall impact whenαis small. The plastic strain distribution of impact crater is more uneven with the increasing of impact angle. In the eccentric impact condition, plastic strain zone of pipeline decreases with the increasing of eccentricityk.